Table 6 MR analysis of the causal association of plasma vitamin C levels with AD, AD proxy phenotype, and cognitive performance using 10 genetic variants excluding the rs174547 variant

IGAP AD

IVW

0.94

0.81–1.10

4.64E−01

Weighted median

1.02

0.83–1.24

8.83E−01

MR-Egger

1.09

0.85–1.40

5.07E−01

MR-PRESSO

0.94

0.81–1.10

4.71E−01

UK Biobank AD proxy

IVW

0.93

0.88–0.98

1.30E−02

Weighted median

0.92

0.87–0.97

2.00E−03

MR-Egger

0.91

0.84–0.98

1.70E−02

MR-PRESSO

0.93

0.88–0.98

3.41E−02

Maternal AD group from UK Biobank

IVW

0.89

0.84–0.94

8.38E−05

Weighted median

0.87

0.82–0.93

3.30E−05

MR-Egger

0.86

0.80–0.93

2.54E−04

MR-PRESSO

0.89

0.85–0.93

1.05E−03

Paternal AD group from UK Biobank

IVW

1.01

0.91–1.12

8.25E−01

Weighted median

1.00

0.92–1.10

9.38E−01

MR-Egger

1.00

0.87–1.15

9.95E−01

MR-PRESSO

1.01

0.91–1.12

8.30E−01

Cognitive performance

IVW

−0.005

[−0.034, 0.025]

0.754

Weighted median

−0.013

[−0.051, 0.025]

0.510

MR-Egger

−0.004

[−0.054, 0.045]

0.865

MR-PRESSO

−0.005

[−0.034, 0.025]

0.761